FtpWebRequest.Abort Metodo

Definizione

Spazio dei nomi:

System.Net

Assembly:

System.Net.Requests.dll

Origine:

FtpWebRequest.cs

Termina un'operazione FTP asincrona.

public:
 override void Abort();

public override void Abort ();

override this.Abort : unit -> unit

Public Overrides Sub Abort ()

Esempio

Nell'esempio di codice seguente viene illustrato come l'utente può terminare un caricamento asincrono di un file dalla directory locale al server.

public:
   void AbortUpload( String^ fileName, String^ serverUri )
   {
      request = dynamic_cast<FtpWebRequest^>(WebRequest::Create( serverUri ));
      request->Method = WebRequestMethods::Ftp::UploadFile;

      // Get the file to be uploaded and convert it to bytes.
      StreamReader^ sourceStream = gcnew StreamReader( fileName );
      fileContents = Encoding::UTF8->GetBytes( sourceStream->ReadToEnd() );
      sourceStream->Close();

      // Set the content length to the number of bytes in the file.
      request->ContentLength = fileContents->Length;

      // Asynchronously get the stream for the file contents.
      IAsyncResult^ ar = request->BeginGetRequestStream( gcnew AsyncCallback( this, &AsynchronousFtpUpLoader::EndGetStreamCallback ), nullptr );
      Console::WriteLine( "Getting the request stream asynchronously..." );
      Console::WriteLine( "Press 'a' to abort the upload or any other key to continue" );
      String^ input = Console::ReadLine();
      if ( input->Equals( "a" ) )
      {
         request->Abort();
         Console::WriteLine( "Request aborted" );
         return;
      }
   }

public class ApplicationMain
{
    public static void Main()
    {
          ManualResetEvent wait = new ManualResetEvent(false);
          AsynchronousFtpUpLoader uploader = new AsynchronousFtpUpLoader(wait);
          uploader.AllowAbortUpload("out.txt", "ftp://sharriso1/ftptests.txt");
          wait.WaitOne();
          if (uploader.AsyncException != null)
          {
                Console.WriteLine(uploader.AsyncException.ToString());
          }
    }
}
    public class AsynchronousFtpUpLoader
    {
        ManualResetEvent wait;
        FtpWebRequest request;
        byte [] fileContents;
        Exception asyncException = null;

        public AsynchronousFtpUpLoader(ManualResetEvent wait)
        {
            this.wait = wait;
        }

        public Exception AsyncException
        {
            get { return asyncException;}
        }

        private void EndGetStreamCallback(IAsyncResult ar)
        {
            Stream requestStream = null;
            // End the asynchronous call to get the request stream.
            try
            {
                requestStream = request.EndGetRequestStream(ar);
            }
            // Return exceptions to the main application thread.
            catch (Exception e)
            {
                Console.WriteLine("Could not get the request stream.");
                asyncException = e;
                wait.Set();
                return;
            }
            // Write the file contents to the request stream.
            requestStream.Write(fileContents, 0, fileContents.Length);
            Console.WriteLine ("Writing {0} bytes to the stream.", fileContents.Length);
            // IMPORTANT: Close the request stream before sending the request.
            requestStream.Close();
        }

        // The EndGetResponseCallback method
        // completes a call to BeginGetResponse.
        private void EndGetResponseCallback(IAsyncResult ar)
        {
            FtpWebResponse response = null;
            try
            {
                response = (FtpWebResponse) request.EndGetResponse(ar);
            }
            // Return exceptions to the main application thread.
            catch (Exception e)
            {
                Console.WriteLine ("Error getting response.");
                asyncException = e;
                wait.Set();
            }
            Console.WriteLine("Upload status: {0}",response.StatusDescription);
            // Signal the application thread that this operation is complete.
            wait.Set();
        }
        internal void AbortRequest(FtpWebRequest request)
        {
            request.Abort();
            Console.WriteLine("Request aborted!");
            wait.Set();
        }

       public void AllowAbortUpload(string fileName, string serverUri)
       {
            request = (FtpWebRequest)WebRequest.Create(serverUri);
            request.Method = WebRequestMethods.Ftp.UploadFile;
            // Get the file to be uploaded and convert it to bytes.
            StreamReader sourceStream = new StreamReader(fileName);
            fileContents = Encoding.UTF8.GetBytes(sourceStream.ReadToEnd());
            sourceStream.Close();
            // Set the content length to the number of bytes in the file.
            request.ContentLength = fileContents.Length;
            // Asynchronously get the stream for the file contents.
            IAsyncResult ar = request.BeginGetRequestStream(
                new AsyncCallback (EndGetStreamCallback), null);
             while (!ar.IsCompleted)
            {
                Console.WriteLine("Press 'a' to abort writing to the request stream. Press any other key to continue...");
                string input = Console.ReadLine();
                if (input == "a")
                {
                    AbortRequest(request);
                    return;
                }
            }
            Console.WriteLine("Sending the request asynchronously...");
            IAsyncResult responseAR = request.BeginGetResponse(
                new AsyncCallback (EndGetResponseCallback), null);

            while (!responseAR.IsCompleted)
            {
                Console.WriteLine("Press 'a' to abort the upload. Press any other key to continue.");
                string input = Console.ReadLine();
                if (input == "a")
                {
                    AbortRequest(request);
                    return;
                }
            }
        }

Commenti

Se non esiste alcuna operazione in corso, questo metodo non fa nulla. Se un trasferimento di file è in corso, questo metodo termina il trasferimento.

Nota

Questo membro genera informazioni di traccia quando viene abilitata la funzionalità di traccia di rete nell'applicazione in uso. Per altre informazioni, vedere Traccia di rete in .NET Framework.

Vedi anche

• FtpWebResponse
• FtpStatusCode
• WebRequestMethods.Ftp
• WebRequest
• WebResponse
• WebClient